The relationship between Usher's syndrome and psychosis with Capgras syndrome.

Usher's syndrome is a genetic disorder that causes congenital sensorineural hearing loss, visual impairment due to progressive pigmentary retinopathy, and, often, vestibular dysfunction. The aim of this article is to illustrate a case that clearly demonstrates psychotic symptoms in Usher's syndrome Type III and serves to increase clinical awareness of this disorder and its possible link to psychotic symptoms. There is some evidence in the literature of concurrent psychiatric symptoms, particularly psychotic symptoms, associated with Usher's syndrome, and several theories around this association have been proposed. These theories of associations include a genetic link between the genes responsible for schizophrenia and the genes for Usher's syndrome; a neuropathological explanation as radiologic studies have revealed that patients with Usher's syndrome have CNS abnormalities in multiple brain structures; and a sensory deficit model which proposes that the stressors associated with sensory impairment and the brain's adaptation to changes in sensory inputs place an individual at increased risk for psychopathology.

Depression, HIV dementia, delirium, posttraumatic stress disorder (or all of the above)

A 29-year-old single Puerto Rican woman with AIDS was admitted to the Medical Service for pneumonia, seen by the Psychiatric Consultation Service, an eventually transferred to the Inpatient Psychiatric Unit with several possible psychiatric diagnoses including major depression, HIV dementia, delirium, and posttraumatic stress disorder. These possibly coexisting and interacting syndromes are discussed by three psychiatrists, one of whom is also a board-certified neurologist. This case illustrates the combined contribution of organic and psychological factor to complex behavioral disorders, which are increasingly common in HIV infection.

Skeletal muscle calcium metabolism and contractile force in vitamin D-deficient chicks.

The myopathy associated with vitamin D deficiency has not been well characterized, and it is not known if weakness is a result of a specific effect of vitamin D deficiency on skeletal muscle. Chicks were raised from hatching on a vitamin D-deficient diet, and by 3 wk of age were hypocalcemic and appeared weak. Tension generated by triceps surae during repetitive stimulation of posterior tibial nerve was significantly less than that developed by chicks given vitamin D(3) supplements (309 g tension/g wet weight of triceps surae, SD 60, for vitamin D-deficient chicks; 470, SD 77, for vitamin D(3)-treated chicks, P < 0.01). Histochemical and electron microscopic examination of skeletal muscles of these chicks showed no abnormalities, and there were no electrophysiologic evidences of motor nerve or neuromuscular junction dysfunction. The concentration of ATP in skeletal muscle of the vitamin D-deficient chicks (5.75 mumol/g wet weight, SD 0.17) was not significantly different from that in vitamin D-treated chicks (5.60, SD 0.50). There was no correlation between strength and serum calcium, serum inorganic phosphate, or skeletal muscle inorganic phosphate. Relaxation of tension after tetanic stimulation was slowed in the vitamin D-deficient chicks (20.6 ms, SD 1.7, vs. 15.4, SD 1.3, in vitamin D-treated chicks and 15.3, SD 1.0, in normal control chicks), and in vitro (45)Ca(++) transport by sarcoplasmic reticulum from the vitamin D-deficient chicks was reduced. Calcium content of mitochondria prepared from leg muscles of vitamin D-deficient chicks (24 nmol/mg mitochondrial protein, SD 6) was considerably lower than that of mitochondria from normal control chicks (45, SD 8) or from chicks treated with vitamin D for 2 wk or more (66-100, depending upon level and duration of therapy). Treatment of the vitamin D-deficient chicks from hatching with sufficient dietary calcium to produce hypercalcemia did not significantly raise skeletal muscle mitochondrial calcium content (31 nmol/mg mitochondrial protein, SD 7) and did not prevent weakness. These studies demonstrate objective weakness as a result of myopathy in vitamin D-deficient chicks, and provide evidence that vitamin D deficiency has effects on skeletal muscle calcium metabolism not secondary to altered plasma concentrations of calcium and phosphate.